In many large, sophisticated systems that are kept in operation over periods of many years, maintenance is a significant portion of the total lifetime cost of the system. This portion is even higher for systems that are utilized for many years in very demanding, mission-critical applications and environments, such as weapons systems, aircraft, and military vehicles (e.g., tanks). According to one estimate provided by the United States Department of Defense, the operations and maintenance comprises up to 70% of the total cost of some weapons systems. In this current era of government budget deficits, there is significant pressure to reduce the costs of such sophisticated systems. Given its large portion of the total costs, maintenance may be a fertile area for realizing cost savings through various improvements in efficiency.
Maintenance of military systems, including aircraft, vehicles, etc., is very complex—and therefore costly—due to a variety of reasons. First, the systems themselves are usually very complex, consisting of numerous assemblies, subassemblies, modules, parts, etc. manufactured and/or assembled by a host of different suppliers. Each of these items may have its own documentation such as data sheets, reference manuals, repair guides, etc. Second, due to the high cost and mission-critical nature of many military systems, it is extremely undesirable for them to be taken out of deployment for any significant period of time. Accordingly, maintenance and repair of such systems must be performed very quickly and efficiently—albeit very precisely and without error. Third, maintenance tasks on such systems are often very unstructured. For example, the maintenance technician who is assigned to repair a military aircraft may be presented with one (or more) of hundreds or even thousands of possible problems, most of which he invariably has not encountered before. Fourth, maintenance and repair of military systems is geographically disperse. For example, the fleet of a particular type of aircraft may be kept at various air bases around the world as well as, in some cases, at a central maintenance depot. Each location must be fully capable of maintenance and repair. Finally, given the importance of such systems to national security, maintenance and repair operations must take place in a secure environment. Due to these complexities, it is difficult to efficiently and quickly perform maintenance and make repairs to complex systems, such as military aircraft, while managing priorities and meeting any performance metrics that may exist.